125kHz EM RFID Reader Modules (UART, TTL, Wiegand)

EM-family reader modules with UART, Wiegand or RS232 choices and onboard or external antennas. Check the actual credential protocol and signal levels before selecting a replacement board.

5 product families · samples available · reply within 24 h
LF-120

125 kHz EM4100 Reader Module with TTL, Wiegand 26 or RS232

40 × 40 mm board-level reader for EM4100/TK4100 cards, ordered with TTL UART, Wiegand 26 or RS232 output, plus card-present and buzzer/LED drive pins.

125 kHz (EM4100/TK4100)TTL / Wiegand 26 / RS232 (by version)> 50 mm
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LF-150

125 kHz RFID Module, UART TTL, 30 × 16 mm, External Antenna

30 × 16 × 8.9 mm EM4100-family reader with a 3.3 V TTL UART, auto or command-triggered reading and serial firmware upgrade, driven by an external 490 µH antenna.

125 kHz (EM4xxx)UART, 3.3 V TTL9600–115200 bps (default 115200)
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LF-110

Dual-Frequency 125 kHz/13.56 MHz Wiegand 26/34 Reader Module

Dual-band OEM reader board that passes 125 kHz EM4100/TK4100 and 13.56 MHz MIFARE, DESFire EV1 and NTAG card numbers to a controller as Wiegand 26 or Wiegand 34.

125 kHz + 13.56 MHzWiegand 26 / Wiegand 34 (selectable)> 20 mm (card- and environment-dependent)
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LF-130

Compact 125 kHz EM4100 Reader Module, TTL or Wiegand 26

32.5 × 17.5 mm EM4100/TK4100 reader board with an external coil antenna, supplied with TTL UART or Wiegand 26 output for space-limited devices.

125 kHz (EM4100/TK4100)TTL UART / Wiegand 26 (by version)> 50 mm
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LF-140

Mini 125 kHz EM RFID Module with Wiegand and UART Output

24.3 × 16 × 11.8 mm, 2.1 g low-frequency module with an external antenna that reads EM4100-family credentials at 0–8 cm and reports over Wiegand or 5 V UART.

125 kHzEM4100/4102/4200/4305/44500–8 cm
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Buyer's notes

How to choose 125khz reader modules

The LF range reads EM-family 125 kHz cards and fobs. Module size, antenna arrangement and output vary: some use an external coil, while LF-120 includes an onboard antenna. LF-110 adds a dual-frequency configuration rather than making every LF module dual-frequency.

Choose the electrical interface from the host design. TTL UART and RS232 are different signaling systems, and Wiegand delivers a card number rather than a general command channel. Verify output format and signal levels before wiring a module into an existing product.

Do not assume every credential labeled 125 kHz uses the same protocol. If a legacy card population includes a different format, evaluate the appropriate multi-technology option with sample cards. The LF chip comparison helps distinguish read-only credentials from programmable chip uses.

Learn & apply

Guides and applications

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Frequently asked questions

Will an EM-family LF module read every 125 kHz card?

No. Carrier frequency alone does not establish protocol support. Use the credential list for the exact module and test representative cards.

Which LF module adds 13.56 MHz reading?

LF-110 lists a dual-frequency 125 kHz/13.56 MHz configuration. Other LF models should be selected from their own listed credential support.

Can an external antenna coil be chosen by size alone?

No. Its electrical characteristics and connection must match the module specification. Test the selected coil in the final installation.

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